Avram Grant has shown already this season that he is a competent first-team coach capable of working in one of the most demanding leagues in the world, but over the next nine days he must demonstrate that he deserves the chance he has been given to operate at its summit.

While taking over from José Mourinho undoubtedly represents a poisoned chalice — as would succeeding Sir Alex Ferguson at Manchester United or Arsène Wenger at Arsenal — it also presents an unrivalled opportunity for collecting more elaborate silverware. Grant may not get another one. For all the invidious comparisons with Mourinho it is not memories of the self-styled Special One that do most damage to Grant, but those of his predecessor, Claudio Ranieri.

Ranieri was a likeable individual working under intolerable pressure — widely admired for remaining genial, down to earth and possessing a wry sense of humour — but ultimately shown to be an ordinary manager at the highest level. Ranieri was a nearly manarther, an epithet Grant will strive to surpass in the three matches that could define the future of Chelsea.

Ranieri met his end after conspiring to lose a Champions League semi-final to AS Monaco that Chelsea were expected to win, lacking any other trophies to rescue his reputation after four years at Stamford Bridge, a situation similar to the one Grant finds himself in prior to this week’s double-header against Liverpool and last stand against Manchester United in the Barclays Premier League on Saturday.

The writing was on the wall for Ranieri when, after conceding two late goals to lose the first leg 3-1, Roman Abramovich asked several players on to his yacht in Monte Carlo for a post mortem, though failed to extend the invitation to the manager. Grant has seen the inside of much of the Russian’s fleet, but that does not mean he will not be thrown overboard.

By comparison, Ranieri even had certain advantages — the vocal backing of Chelsea fans and widespread respect for taking the club into the Champions League for only the second time in their history on the back of limited investment before finishing as runners-up to Arsenal’s “Invincibles”.

In his penultimate season, the last of the pre-Abramovich era, Ranieri’s only signing was Enrique De Lucas, an undistinguished Spanish midfield player, whereas Grant inherited the most expensively-assembled squad in world football and quickly added Nicolas Anelka. Not even Mourinho was permitted such luxuries mid-season.

It is often overlooked that Abramovich was preparing to give Ranieri a last-minute reprieve had Chelsea reached the 2004 final — against Mourinho’s FC Porto, remember — making him a far more patient owner than Thaksin Shinawatra. Given his desire for Grant to succeed, the Israeli will also be given a second chance if he takes his side to Moscow next month, irrespective of their fate in the title race, but it will be fascinating to see how Abramovich reacts to another semi-final defeat.

A haul of two domestic cups under Mourinho last year was dismissed as not good enough and paved the way for his early-season exit, but will Grant be treated differently? Abramovich’s response to any setback will reveal whether he is prepared to accept second best in exchange for a quiet life or really wants to run the world’s leading club. Giving Grant a season to steady the ship can be justified as he has done that admirably, but retaining him without a single trophy would risk making Chelsea a laughing stock, a rich man’s play-thing rather than a serious football club.

As for Grant, the biggest clue as to his standing, if he leaves, will be provided by his destination. For all his faults, Ranieri has since found work at Valencia, Parma and Juventus, while Mourinho turned down the England job within three months and is hanging on for Real Madrid or Inter Milan. If all goes wrong who, other than Abramovich, would employ Grant?